Campsite AtlasFlat Rock (Idaho)
Flat Rock Campground is located 22 miles south of West Yellowstone, Montana and 30 miles north of Ashton, Idaho in beautiful Island Park, Idaho. Flat Rock is adjacent to U.S. Highway 20 and the Henry's Fork of the Snake River at an elevation of 6,400 feet. Henry's Fork has great fly-fishing for rainbow and brook trout. The river's headwaters are at Big Springs, one of the nation's largest springs, just 4.5 miles from the campground. Tubing, canoeing, kayaking and rafting are also popular on the river. The Big Springs National Recreation Water Trail begins at Big Springs and ends just northeast of the campground at Macks Inn.
Campsites
| Host/management | 25 |
| Standard, no hookups | 10 |
| Standard with electric | 6 |
| Total | 41 |
Amenities & rules
Compiled from site-level records; individual sites vary. Confirm on Recreation.gov or with the managing office.
Getting there
From West Yellowstone, Montana, take U.S. Highway 20 south for 22 miles, or from Ashton, Idaho, take U.S. Highway 20 north for 30 miles. The campground entrance is 1/4 mile south of Macks Inn on the west side of the highway.
Campgrounds nearby
Data source: Recreation.gov RIDB, retrieved August 30, 2026. The Campsite Atlas is an independent publication and is not affiliated with or endorsed by the Recreation.gov or any federal agency. Always confirm critical details on the official Recreation.gov page before you travel.